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UNITED STATES PATENT y ABENJAMIN A. LEGG, OF COLUMBUS, OHIO, ASSIGNOB `TO JOSEPH A.

JEFFREY, OF SAME PLACE. i

SPROCKET-WHEEL.

SPECIFICATION forming part of Letters Patent No. 296,192, dated April 1, 1884.

Application filed February 14, Iseli. (No model.)

To au whom t may concern.-

Be it known that I, BENJAMIN A. LEGG, a citizen of the United States, residing at Columbus, in the county of Franklin and State of Ohio, have invented certain new and useful Improvements in Sprocket Vheels, of which the following is a specification, reference being had therein to the accompanying drawings.

Figure I is a side elevation of so much of a sprocket-wheel asis necessary to illustrate its construction. Fig. 2 is a vertical section of two such sprocket-wheels, having a drivingchain applied thereto. Fig. 3 is a plan View of the chain.

A is the hub, A the sp'okes, A2 the rim, and A3 the sprocket-teeth, of the Wheel. The working-faces ofthe teeth-that is, the faces which engage with the roller-are at their upper ends curved, as indicated at a a, these curves representing, by preference, arcs of 'circles the centers of which are located between the edges of each tooth, respectively. The base of each tooth is formed upon a reverse curvethat is to say, a line whichv curves in the opposite direction from that described by the upper end of the tooth; but the curved line upon one side of each tooth approaches nearer to the center of the wheel than does the curved line upon the' opposite side of the tooth, as I have found that such construction facilitates the smooth and satisfactory running of the chain. e

The chain which I propose to employ upon wheels of this construction is that which was patented to me in Patent No. 282,536, in which the pintles or pins which connect the links are each provided with and surrounded by an anti-friction roller, and in order to secure the best results I prefer that the curved side at the base of each tooth shall be formed on an arc of a circle of the saine size as the periphery of the anti-friction roller, as is plainly indicated in Fig. 2. By an examination of this gure it will be readily seen that the bases of the opposite sides of each tooth are described from different points, so that while the seat upon one side of the tooth shall be nearer to the center of the Wheel than the seat upon the opposite side all of the seats shall fit accurately the outer' surfaces of the anti-friction rollers, this construction insuring a smoother and more satisfactory running of' the chain, particularly at high speeds and under great tension, than can be obtained in other constructions of which I have knowledge.

In using these wheels I propose to run them in the direction indicated by the arrows on Fig. l', power being applied to the right-hand wheel.

' What I claim is- The herein-describedA sprocket-wheel, having the working-faces of its teeth curved, and provided upon opposite sides with curved seats adapted to receive the anti-friction rollers ofthe driving-chain, the seat upon one side being nearer to the center of the wheel than the seat upon the opposite side of the tooth, substantially as set forth.

In testimony whereof I ax my signature in presence of two lwitnesses.

.BENJAMIN A. LEGG.

Witnesses:

J. M. TIBBE'rrs, CHARLES W. MTLLER. 

